Position-adaptive robotic sensor concepts for radar applications are known and have been investigated to a small degree in the prior art. Present-day combat scenarios often involve a foot soldier patrolling within hostile urban environments. The development of position-adaptive radar concepts allow for several advancements in the area of intelligent preparation for the battlefield by providing soldiers the capability of safely pre-surveying embedded urban canyons and obscured indoor environments for unforeseen adversaries and obscured weapons from a reasonable stand-off distance. This technology also allows for the continuous electronic surveillance of activities within an uncontrolled region and also for monitoring of suspicious materials transfers within uncontrolled regions of interest. In general, multi-platform position-adaptive UAV radar concepts allow for the acquisition of intelligence information in many important and challenging environments with obscured and embedded channels and allow for the safe preparation of an uncontrolled region-of-interest for day to day military operations. Position-adaptive multi-UAV radar is also a dual-use technology in the sense that many system configurations and geometries can be defined with important applications to commercial security and homeland defense.
FIG. 1 illustrates a prior art position-adaptive radar system concept for interrogating difficult and obscured targets in urban environments using low-altitude smart, or robotic-type, unmanned air vehicle (UAV) platforms. The UAVs are shown at 100 and 101 and the urban environment is shown at 102. A low-altitude position-adaptive platform is denoted as a “LUAV” and a high-altitude radiating platform as “HUAV.” The system concept entails two modes. In mode 1, LUAVs perform real-time onboard computations of differential phase parameters, phase discontinuities, and amplitude signatures to position-adaptively isolate signal leakage points (e.g., between two buildings).
After the LUAV position-adaptively converges to an optimum location (at a leakage point), the system enters mode 2 (see FIG. 1). The mode 2 technique is based on modulating scattering centers on embedded objects 103 (denoted by the small black box in the figure) by implementing a fast trajectory on the HUAV as the LUAV hovers in front of an obscured channel. This fast trajectory on the HUAV generates a modulation signal that a smart LUAV can measure in a passive mode and analyze. Under this concept, the hovering LUAV measures the modulation signals and implements a set of real-time onboard computations to determine characteristics of embedded target that are non-line-of-sight to either the HUAV or the LUAV.
Position-adaptive radar system development efforts for future systems include analysis, simulations, and data collection efforts for interrogating indoor urban environments, tunnels, embedded cavities, and other challenging clutter environments. Position-adaptive sensor concepts for interrogating embedded objects-of-interest in challenging environments using electro-optic and laser sensors can also be formulated and investigated for advanced sensor development applications. Developing a hybrid air/ground position-adaptive UAV radar capability with regenerative energy sources addresses many of the limitations of existing UAV-based sensor systems due, for example, to energy-limited loiter and reconnaissance times within an embedded urban environment. In addition, a hybrid air/ground capability enhances the flexibility of a distributed multi-UAV system by allowing for a continuum of platform altitudes.
The present invention introduces a platform design that will significantly improve the versatility and endurance of future robotic or robotically-enhanced (partially autonomous) positive-adaptive sensor designs.